A woman is reincarnated into a romance fantasy as an extra completely unrelated to the original story, where a war-loving tyrant emperor is destined to fall in love with the saintly heroine. For her, surviving everyday life and avoiding overtime matter far more than the grand romance of the original plot. But her ordinary routine changes when she suddenly ends up with a handsome boyfriend who seems almost too perfect to be real. What she does not realize is that her sweet and lovable boyfriend is actually the emperor himself. Thus begins a secret romance born from misunderstanding, as she struggles to protect her boyfriend from the dangerous emperor—without knowing they are the same person.